Compatibility

Terminal compatibility and benchmarks

Which terminal sequences Wormhole supports, where support is partial, and what our recorded tests measured.

On this page

01/Overview

Compatibility at a glance

Core terminal behavior is supported. Graphics and extended input protocols have the limits listed below.

Supported behavior

Cursor movement, scrolling regions, alternate screens and bracketed paste.
True color, styled underlines, hyperlinks and shell integration.
Unicode character widths and grapheme clusters, with results from ucs-detect below.
Inline images through kitty, iTerm2 and Sixel protocols, with the limits listed alongside.

Browse the protocol reference

Known limits

kitty graphics: no animation, file or shared-memory transfers, or relative placements.
Sixel: no private palettes. Images are not restored after restarting the app.
kitty keyboard protocol: no key-release, repeat or standalone modifier events.
Screen checksums and window operations require opt-in settings.

The results below were recorded on October 15, 2026 using Mac17,8, Apple M5 Pro, macOS 27.0.1. Wormhole was a 1.0 pre-release build. These are results for the listed builds and settings, not measurements of the latest releases.

02/Test suites

Terminal behavior tests

Wormhole passed 538 of 566 measured esctest2 cases. All recorded ucs-detect width cases matched the expected widths.

esctest2 tests terminal control sequences, including cursor movement, erasing and scrolling, against xterm behavior. ucs-detect compares reported cursor positions with the widths expected by the wcwidth library. Neither suite establishes that every application or font renders correctly.

esctest2

Some esctest2 cases require screen checksums or other query responses. Cases that a terminal cannot expose to the suite are marked unmeasurable, not failed. The percentages therefore use different denominators. Use the Common cases column to compare the 323 cases measured in every completed run. Wormhole’s screen-checksum setting was enabled for this run; it is off by default. Wormhole failures by area: Reports: 2 of 30; Colors, titles, selection: 21 of 51; Window operations: 5 of 28.

Cases passed out of 323

The same test subset for each completed run. Bars show passed cases; interrupted runs have no score.

Wormhole295/323
Ghostty141/323
Alacritty121/323
kitty135/323
WezTerm174/323
iTerm2Not measured
Terminal.app111/323

Scroll horizontally to see all columns.

Terminal	Common cases (323)	Version	Passed	Failed	Unmeasurable	Measured	Pass rate
Wormhole	295/323 (91.3%)	1.0 pre-release	538	28	0	566	95.1%
Ghostty	141/323 (43.7%)	1.3.1	141	185	240	326	43.3%
Alacritty	121/323 (37.5%)	0.17.0	121	215	230	336	36.0%
kitty	135/323 (41.8%)	0.49.2	135	194	237	329	41.0%
WezTerm	174/323 (53.9%)	20240203-110809-5046fc22	340	226	0	566	60.1%
iTerm2	–	3.7.4	Not measured yet	–	–	–	–
Terminal	111/323 (34.4%)	2.15	111	217	238	328	33.8%

October 15, 2026 · Mac17,8, Apple M5 Pro, macOS 27.0.1 · esctest2 2798f12149a1 (Thomas Dickey, GPL-2.0) · 80 x 25 cells, Menlo 13 pt · load average at the start 4.01 3.53 3.48

esctest2 query support and results by area

Scroll horizontally to see all columns.

Terminal	cursor position (DSR 6)	DA1	text area size (CSI 18 t)	CSI 14 t	CSI 16 t	checksum of a rectangle (DECRQCRA)	checksum form
Wormhole	Yes	Yes	Yes	Yes	Yes	Yes	positive
Ghostty	Yes	Yes	Yes	Yes	Yes	No	-
Alacritty	Yes	Yes	Yes	Yes	No	No	-
kitty	Yes	Yes	Yes	Yes	Yes	No	-
WezTerm	Yes	Yes	Yes	Yes	Yes	Yes	positive
iTerm2	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown	Unknown
Terminal	Yes	Yes	Yes	Yes	No	No	-

Scroll horizontally to see all columns.

Area (tests)	Wormhole	Ghostty	Alacritty	kitty	WezTerm	Terminal
Cursor movement (132)	132/132	75/95	57/104	72/95	131/132	67/96
Erasing and editing (129)	129/129	4/8	1/8	4/8	79/129	3/8
Rectangular operations (32)	32/32	4/4	3/4	4/4	8/32	4/4
Margins (9)	9/9	1/1	1/1	1/1	9/9	1/1
Modes and resets (120)	120/120	29/89	24/90	25/92	63/120	22/90
Tabs (6)	6/6	3/6	5/6	5/6	6/6	5/6
Cursor save and restore (22)	22/22	12/14	9/14	8/14	20/22	8/14
Reports (30)	28/30	5/30	1/30	4/30	3/30	0/30
Colors, titles, selection (52)	30/51	8/51	20/51	12/51	14/51	0/51
Strings (APC, DCS, PM, SOS) (7)	7/7	-	-	-	7/7	-
Window operations (28)	23/28	0/28	0/28	0/28	0/28	1/28

ucs-detect

Percentages show how often reported widths matched the suite’s expected widths. Italic rows are results published by the ucs-detect author on other machines and versions. They are reference data, not controlled comparisons with this run. WezTerm's run did not finish (no result within 1800s), so it has no row.

Scroll horizontally to see all columns.

Terminal	wide	narrow	ZWJ emoji	VS16	VS15	flags (RI pairs)	lone RI	lone skin tone	languages	grapheme clustering (mode 2027)	ambiguous width	seconds
Wormhole	100.0% (506/506)	100.0% (5595/5595)	100.0% (1445/1445)	100.0% (426/426)	100.0% (158/158)	100.0% (262/262)	100.0% (26/26)	100.0% (5/5)	100.0% (6589/6589)	enabled	narrow	0
Ghostty	99.8% (505/506)	99.9% (5590/5595)	100.0% (1445/1445)	100.0% (426/426)	100.0% (158/158)	100.0% (262/262)	100.0% (26/26)	100.0% (5/5)	98.4% (6485/6589)	enabled	narrow	1
Ghostty published (1.3.1-arch2, Linux)	99.8% (505/506)	99.9% (5524/5529)	100.0% (1445/1445)	100.0% (426/426)	100.0% (158/158)	100.0% (262/262)	100.0% (26/26)	100.0% (5/5)	99.5% (6490/6522)	enabled	narrow	7
Alacritty	94.9% (480/506)	99.6% (5570/5595)	0.7% (10/1445)	50.0% (213/426)	0.0% (0/158)	100.0% (262/262)	0.0% (0/26)	100.0% (5/5)	84.4% (5558/6589)	no	narrow	1
Alacritty published (, Linux)	94.9% (480/506)	99.5% (4975/5000)	1.0% (10/1010)	50.0% (213/426)	0.0% (0/158)	100.0% (262/262)	0.0% (0/26)	100.0% (5/5)	85.3% (5563/6522)	no	narrow	2
kitty	99.0% (501/506)	99.6% (5570/5595)	100.0% (1445/1445)	97.9% (417/426)	100.0% (158/158)	100.0% (262/262)	100.0% (26/26)	0.0% (0/5)	45.4% (2990/6589)	no	narrow	47
kitty published (0.48.2, Linux)	97.8% (43587/44568)	99.9% (36227/36254)	100.0% (1445/1445)	97.9% (417/426)	100.0% (158/158)	100.0% (262/262)	100.0% (26/26)	0.0% (0/5)	79.5% (19898/25043)	no	narrow	629
iTerm2	Not measured yet	–	–	–	–	–	–	–	–	–	–	–
iTerm2 published (3.7.3, Darwin)	97.8% (43591/44568)	100.0% (36237/36254)	17.2% (249/1445)	100.0% (426/426)	0.0% (0/158)	100.0% (262/262)	100.0% (26/26)	100.0% (5/5)	93.7% (23462/25043)	no	narrow	22377
Terminal	94.9% (480/506)	98.3% (5500/5595)	0.0% (0/1445)	50.0% (213/426)	0.0% (0/158)	98.9% (259/262)	0.0% (0/26)	100.0% (5/5)	81.0% (5334/6589)	no	narrow	9
Terminal published (488, Darwin)	97.8% (43566/44568)	99.7% (36159/36254)	0.0% (0/1445)	50.0% (213/426)	0.0% (0/158)	98.9% (259/262)	0.0% (0/26)	100.0% (5/5)	93.4% (23400/25043)	no	narrow	37

October 15, 2026 · Mac17,8, Apple M5 Pro, macOS 27.0.1 · ucs-detect 50f011d991a2 (Jeff Quast, MIT), its default run (the contested codepoints and graphemes), wcwidth 0.8.4 · 80 x 25 cells, Menlo 13 pt · load average at the start 4.01 3.53 3.48

Completed, interrupted and failed suite runs

Scroll horizontally to see all columns.

Suite	Terminal	Result	Version	Seconds
esctest	Wormhole	ok	1.0 pre-release	87
esctest	Ghostty	ok	1.3.1	134
esctest	Alacritty	ok	0.17.0	96
esctest	kitty	ok	0.49.2	106
esctest	WezTerm	ok	20240203-110809-5046fc22	278
esctest	iTerm2	Not measured yet	3.7.4	–
esctest	Terminal.app	ok	2.15	267
ucs-detect	Wormhole	ok	1.0 pre-release	21
ucs-detect	Ghostty	ok	1.3.1	7
ucs-detect	Alacritty	ok	0.17.0	8
ucs-detect	kitty	ok	0.49.2	165
ucs-detect	WezTerm	failed: no result within 1800s	20240203-110809-5046fc22	1930
ucs-detect	iTerm2	Not measured yet	3.7.4	–
ucs-detect	Terminal.app	ok	2.15	57

iTerm2’s suite results are excluded because permission prompts interrupted the run. Its benchmark results are included in the next section. Load average at the start: 4.01 3.53 3.48.

03/Benchmarks

Performance benchmarks

Measured output throughput and response times for the listed app builds, followed by engine-only tests. Recorded on October 15, 2026 with Wormhole 1.0 pre-release, Ghostty 1.3.1, Alacritty 0.17.0, kitty 0.49.2, WezTerm 20240203-110809-5046fc22, iTerm2 3.7.4, Terminal.app 2.15. Newer releases may be faster or slower.

In the app

ttystorm, our benchmark tool, sends workloads to each running app and waits for terminal responses. It does not measure keypress-to-pixel latency or frames actually displayed. Higher values are better except for roundtrip, where lower is better. Wormhole led 14 of 17 workloads in this run. Other workload leaders: iTerm2 on agentstream; Alacritty on stylestorm and linkstorm.

Relative benchmark score

Approximate geometric mean across the recorded workloads. The vertical marker is Terminal.app at 1×; higher scores are better. This is not a measure of typing latency.

Wormhole≈ 6.3×
Ghostty≈ 3.6×
Alacritty≈ 4.8×
kitty≈ 2.9×
WezTerm≈ 1.2×
iTerm2≈ 0.5×
Terminal.app≈ 1.0×

Scroll horizontally to see all columns.

Test	Wormhole	Ghostty	Alacritty	kitty	WezTerm	iTerm2	Terminal.app
buildlogA cargo-style build log: colored lines and a progress bar redrawn in place.	188 MB/s	109 MB/s	171 MB/s	109 MB/s	29.9 MB/s	22.0 MB/s	44.3 MB/s
agentstreamAn agent's answer in 2 to 16 byte writes, with a spinner redrawn under it.	9.0 MB/s	8.9 MB/s	9.5 MB/s	9.0 MB/s	9.6 MB/s	9.8 MB/s	8.2 MB/s
agentredrawA coding agent's main-screen UI, a dozen styled rows redrawn in full every frame.	90006 fps	46689 fps	55055 fps	41699 fps	14557 fps	10415 fps	17809 fps
agentscreenThe same agent's full-screen UI: many tiny positioned writes.	201502 fps	98994 fps	103473 fps	73654 fps	33001 fps	17536 fps	31470 fps
diffscrollPaging through a colored diff in a pager.	188 MB/s	104 MB/s	166 MB/s	97.7 MB/s	24.7 MB/s	26.1 MB/s	46.1 MB/s
editstormAn editor at work: scroll region, insert and delete lines and characters, repaints.	189 MB/s	114 MB/s	180 MB/s	90.7 MB/s	51.4 MB/s	17.1 MB/s	32.7 MB/s
logfloodPlain log lines, like cat of a big file.	227 MB/s	129 MB/s	183 MB/s	160 MB/s	50.1 MB/s	68.4 MB/s	48.1 MB/s
glyphstormCJK, emoji, combining marks, box drawing.	166 MB/s	130 MB/s	101 MB/s	92.4 MB/s	9.6 MB/s	11.5 MB/s	25.2 MB/s
colorfloodEvery character with its own 24-bit foreground and background.	272 MB/s	97.7 MB/s	163 MB/s	119 MB/s	146 MB/s	39.0 MB/s	3.1 MB/s
scrollstormLines pushed through a scroll region with reverse index.	221 MB/s	126 MB/s	170 MB/s	161 MB/s	46.6 MB/s	9.9 MB/s	46.7 MB/s
cursorstormRandom cursor moves with short colored writes.	192 MB/s	111 MB/s	175 MB/s	105 MB/s	36.5 MB/s	26.2 MB/s	21.3 MB/s
longlinesLines of 5 to 50 thousand characters that wrap.	231 MB/s	136 MB/s	178 MB/s	162 MB/s	51.1 MB/s	108 MB/s	49.9 MB/s
stylestormEvery SGR attribute, densely mixed.	143 MB/s	85.3 MB/s	152 MB/s	85.2 MB/s	54.0 MB/s	17.9 MB/s	25.8 MB/s
linkstormOSC 8 hyperlinks on short spans, thousands of distinct URLs.	152 MB/s	44.0 MB/s	178 MB/s	105 MB/s	69.5 MB/s	16.3 MB/s	41.5 MB/s
framerateFull-screen redraws in synchronized output, in frames per second.	1101 fps	568 fps	560 fps	680 fps	828 fps	115 fps	35.3 fps
screenswapOpening and closing a full-screen program over and over.	28922 /s	18251 /s	17576 /s	13454 /s	4487 /s	93.1 /s	5491 /s
roundtrip1,000 cursor-report round trips on an idle terminal (lower is better).	12 µs	16 µs	20 µs	678 µs	3785 µs	14239 µs	45 µs
Geometric mean, Terminal.app = 1×	6.3×	3.6×	4.8×	2.9×	1.2×	0.5×	1.0×

The summary is a geometric mean of relative results, with latency ratios inverted. Displayed ratios are approximate because the source table rounds its summary values. This score describes these workloads, not overall responsiveness.

App versions, settings and benchmark conditions

Scroll horizontally to see all columns.

App	Result	Version	Grid seen	In front	Load at start
Wormhole	ok	1.0 pre-release	40x120	yes	3.90
Ghostty	ok	1.3.1	40x120	yes	3.91
Alacritty	ok	0.17.0	40x120	yes	3.87
kitty	ok	0.49.2	40x120	yes	3.81
WezTerm	ok	20240203-110809-5046fc22	40x120	yes	3.77
iTerm2	ok	3.7.4	40x120	yes	3.61
Terminal.app	ok	2.15	40x120	yes	3.35

Apps ran one at a time in the foreground, without custom settings where the harness could disable them. It requested the same grid and font; iTerm2 and Terminal.app retained their profile fonts. The table records the actual grids. Wormhole was a 1.0 pre-release build. iTerm2 and Terminal.app ran later the same day.

October 15, 2026 · Mac17,8, Apple M5 Pro, macOS 27.0.1 · load average at the start 4.24 10.19 11.40 · asked for 120 x 40 cells, Menlo 13 pt (an app that can't be told from the command line has its own)

Engine throughput and memory allocations

Engine throughput

These tests feed output directly to each engine without rendering a window. Each workload contains 8 MiB each, sent in 64 KiB pieces. Results use the fastest of 5 passes. Higher throughput is better; the largest value in each row is bold. Wormhole led 7 of 9 workloads. Other workload leaders: Ghostty on unicode-mix and payloads.

Scroll horizontally to see all columns.

MB/s	Alacritty	Wormhole	WezTerm	vt100	Ghostty
ascii-floodPrintable ASCII with no line breaks: the terminal wraps it.	233	2764	67	257	1800
log-linesTimestamped log lines of varying length, some colored.	248	1528	66	241	1207
sgr-churn256-color and true-color foregrounds and backgrounds, attributes and underline styles changing every few characters.	232	379	49	253	165
unicode-mixCJK, emoji (ZWJ, flags, skin tones, VS16), combining marks and box drawing among ASCII.	207	330	70	212	414
tui-redrawA full-screen program redrawing with cursor addressing on the alternate screen.	244	754	42	210	465
scroll-regionOutput scrolling inside scroll regions with IL, DL, SU, SD and RI.	212	809	57	220	648
osc8-linksOSC 8 hyperlinks, titles, working directories and prompt marks.	191	469	70	299	27
payloadsLong OSC, DCS and APC strings (kitty graphics chunks, Sixel, clipboard) between lines of text.	422	569	291	389	1008
agent-sessionA coding agent's session: streamed markdown, spinners, diffs, boxes, progress bars, an image.	320	534	71	353	231
vs the first engine	1.00x	2.85x	0.29x	1.06x	1.62x

Allocation counts show allocator calls per megabyte on the first and second passes. They do not measure stuttering or total memory use. Wormhole recorded zero calls on the second pass for 5 of 9 workloads; Ghostty did so for 6. Ghostty’s direct memory mappings are not included, so the counts do not cover the same allocation mechanisms for every engine.

Scroll horizontally to see all columns.

Calls per MB	Alacritty	Wormhole	WezTerm	vt100	Ghostty
ascii-flood	1193 / 0	19 / 0	25211 / 25214	12499 / 12500	0 / 0
log-lines	1193 / 0	56 / 0	29234 / 29238	11165 / 11168	0 / 0
sgr-churn	2810 / 1617	173 / 0	467143 / 490230	13381 / 13383	0 / 0
unicode-mix	18075 / 16882	1212 / 50	49829 / 49832	10319 / 10320	0 / 0
tui-redraw	0 / 0	1 / 0	112 / 77	5 / 0	1 / 0
scroll-region	119 / 0	0 / 0	48625 / 48635	21633 / 21633	0 / 0
osc8-links	71995 / 70802	13806 / 13560	285969 / 285972	8306 / 8308	18912 / 18908
payloads	687 / 566	1673 / 1641	6356 / 6374	160 / 162	483 / 483
agent-session	4324 / 3131	1421 / 1210	35370 / 36211	4298 / 4300	1301 / 1301

October 15, 2026 · Mac17,8, Apple M5 Pro, macOS 27.0.1 · aarch64, 18 cores · load average at the start 3.89 11.22 11.83

Background load, settings and benchmark variation can affect both values and rankings. The results shown here do not include confidence intervals.

04/Engine tests

Engine tests: 758 of 758 passed

Wormhole’s development tests, run against five terminal engines as libraries.

We wrote these tests while developing Wormhole. They are useful regression checks, but they are not an independent assessment of compatibility. 655 cases follow published specifications; 103 cover behavior we chose where the documentation did not specify an outcome.

The references include xterm, DEC manuals, ECMA-48, Unicode and individual protocol specifications. Each engine runs as a library without its app or renderer. n/a means the test cannot be applied through that engine’s interface; it is not counted as a failure.

Results by area and engine versions

Scroll horizontally to see all columns.

Area	Cases	Wormhole	Ghostty	WezTerm	Alacritty	vt100
altscreen	17	17/17	16/17	16/17	13/17	11/17
charsets	44	44/44	22/44	16/44	13/44	5/41 (+3 n/a)
checksum	17	17/17	2/17	2/17	2/17	0/0 (+17 n/a)
conformance-levels	14	14/14	1/14	2/14	0/14	0/4 (+10 n/a)
cursor	56	56/56	55/56	53/56	45/56	41/56
edit	33	33/33	27/33	23/33	22/33	17/33
erase	31	31/31	30/31	19/31	18/31	17/31
graphics	11	11/11	10/11	5/11	5/11	4/8 (+3 n/a)
margins	31	31/31	23/31	25/31	5/31	5/31
modes	13	13/13	10/13	9/13	9/13	6/6 (+7 n/a)
origin	12	12/12	12/12	12/12	9/12	8/11 (+1 n/a)
osc	29	29/29	22/29	20/29	26/29	8/11 (+18 n/a)
parser	27	27/27	26/27	24/27	25/27	25/27
rect-attributes	45	45/45	8/45	8/45	9/45	10/34 (+11 n/a)
rect	56	56/56	15/56	15/56	15/56	15/55 (+1 n/a)
reports	70	70/70	47/70	33/70	30/70	1/1 (+69 n/a)
reset	22	22/22	22/22	19/22	14/22	14/20 (+2 n/a)
resize	12	12/12	11/12	11/12	11/12	4/12
save-restore	16	16/16	14/16	15/16	14/16	9/14 (+2 n/a)
scroll	28	28/28	27/28	28/28	28/28	21/28
sgr	65	65/65	65/65	65/65	62/65	42/46 (+19 n/a)
tabs	23	23/23	23/23	22/23	21/23	10/23
unicode	52	52/52	46/52	20/52	29/52	26/50 (+2 n/a)
window	12	12/12	3/12	3/12	3/12	0/0 (+12 n/a)
wrap	22	22/22	21/22	19/22	19/22	14/22
all	758	758/758	558/758	484/758	447/758	313/581 (+177 n/a)
spec	655	655/655	470/655	411/655	378/655	267/491 (+164 n/a)
convention	103	103/103	88/103	73/103	69/103	46/90 (+13 n/a)

October 15, 2026 · Mac17,8, Apple M5 Pro, macOS 27.0.1

The engines

Wormhole: Wormhole engine used in this test run
Ghostty: libghostty-vt @ad97d331 (Ghostty's terminal)
WezTerm: wezterm-term @e2a98e1b (WezTerm's terminal model)
Alacritty: alacritty_terminal 0.26.0
vt100: vt100 0.16.2

WezTerm's engine runs with its default settings, as in the app. Alacritty's engine is the one Wormhole used until 1.0.

05/Protocol reference

Terminal protocol reference

Supported sequences, partial implementations and opt-in behavior, grouped by function.

Yes Supported as described.

Partial Supported with the listed limits.

Opt-in Requires a setting; see the notes.

No Not implemented or intentionally ignored.

Unknown No recorded measurement.

05.01/7 features

Cursor and text

Cursor positioning, tab stops, wrapping and saved cursor state.

Related development tests: 56 cursor, 12 origin, 22 wrap, 23 tabs, 16 save-restore, 27 parser cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Cursor movement	CUU CUD CUF CUB CNL CPL CHA CUP VPA VPR HPR HPA HVP	Yes
Index, reverse index, next line	IND NEL RI HTS DECBI DECFI	Yes
Save and restore the cursor	DECSC DECRC SCOSC SCORC	Yes	CSI s is DECSLRM instead while margins are on.
Tab stops	HT CHT CBT TBC DECST8C	Yes
Origin mode, autowrap, reverse wrap	modes 6, 7, 41, 45, 1045	Yes
Cursor shape and blink	DECSCUSR, modes 12, 25	Yes	Block, bar or underline, blinking or not.
Screen alignment test	DECALN	Yes

05.02/4 features

Erase, insert and delete

Sequences for clearing cells, inserting text and deleting lines or columns.

Related development tests: 31 erase, 33 edit cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Erase and edit	ED EL ECH ICH DCH IL DL SU SD REP	Yes	ED 3 clears scrollback. On the main screen, ED 2 moves non-empty lines into scrollback before clearing, unless immediately preceded by ED 3.
Selective erase and protection	DECSED DECSEL DECSCA	Yes	Erases skip protected cells.
Insert and delete columns	DECIC DECDC	Yes
Guarded areas	SPA EPA	Yes	ED, EL and ECH preserve cells written between SPA and EPA.

05.03/3 features

Scrolling and margins

Vertical scroll regions and left and right margins.

Related development tests: 28 scroll, 31 margins cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Scrolling region	DECSTBM	Yes
Left and right margins	DECLRMM (mode 69), DECSLRM	Yes	Scrolling, insert and delete, and wrapping stay inside them.
Shift columns	SL SR	Yes	Shifts columns within the margins on each line of the scroll region. Newly exposed cells use the current background color.

05.04/5 features

Rectangular editing

Operations on rectangular screen areas, including attribute changes and checksums.

Related development tests: 56 rect, 45 rect-attributes, 17 checksum cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Erase a rectangle	DECERA DECSERA	Yes	DECSERA leaves protected cells alone.
Fill a rectangle	DECFRA	Yes
Copy a rectangle	DECCRA	Partial	Only pages 0 and 1 are accepted. Other source or destination pages are ignored.
Change or reverse attributes in an area	DECCARA DECRARA DECSACE	Partial	Bold, underline, blink, negative and hidden; other attributes are ignored.
Checksum of a rectangle	DECRQCRA	Opt-in	Enable in Settings → Terminal → Privacy. Screen-checksum queries can reveal terminal contents to local or remote programs. Some test suites require them.

05.05/11 features

Modes

Terminal modes that programs can set, reset and query.

Related development tests: 13 modes, 17 altscreen, 22 reset, 12 resize, 14 conformance-levels cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Alternate screen	modes 47, 1047, 1048, 1049	Yes	Each screen keeps its own pictures and keyboard flags.
Bracketed paste	mode 2004	Yes
Synchronized output	mode 2026	Yes	An unfinished synchronized update times out rather than leaving output hidden indefinitely.
Application cursor keys and keypad	modes 1, 66, 67	Yes
Reverse video, insert, new line	modes 5, ANSI 4, ANSI 20	Yes
132 columns	DECCOLM, modes 3, 40, 95	Partial	Clears the screen and moves the cursor home without changing the pane’s column count.
Save and restore modes	XTSAVE XTRESTORE	Yes
Soft and full reset	DECSTR, RIS	Yes	RIS clears program status records; a soft reset preserves them.
Conformance level	DECSCL	Yes	VT100 through VT500 levels. The selected level changes DA1 and DA2 replies and disables capabilities from higher levels.
7-bit and 8-bit controls	S7C1T S8C1T	Yes	Replies use 8-bit control characters when requested.
Recorded, with no effect	modes 4, 8, 9, 1010, 1011, 1015, 1016, 1036, 1039, 1042, 1070, 2031, and the VT510's set-up modes	No	Set and reset are remembered and DECRQM reports them; nothing changes. Modes 60, 1001, 1034, 1035, 1037 and 1038 report as permanently reset.

05.06/11 features

Reports and queries

Responses to queries about cursor position, terminal state and supported capabilities.

Related development tests: 70 reports, 12 window cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Device attributes and version	DA1 DA2 DA3 XTVERSION	Yes	DA1 answers as a VT520: Sixel, selective erase, rectangular editing, the locator, color and clipboard access.
Status and cursor position	DSR 5, 6, ?6 and the other ? reports	Yes
Mode reports	DECRQM	Yes	ANSI and DEC private modes.
Setting reports	DECRQSS	Yes	SGR, margins, cursor style, protection, conformance level, rows and columns, attribute extent.
Terminfo capabilities	XTGETTCAP	Partial	Reports a limited set: names, colors, true color, underline styles, bracketed paste, focus reports and synchronized output. Other capabilities receive a negative response.
Sixel graphics attributes	XTSMGRAPHICS	Yes	256 color registers, the screen's size in pixels.
Terminal state reports	DECRQPSR DECRQTSR DECRQDE	Yes	Cursor information, tab stops, the terminal state and the displayed extent, from the VT300 and VT400 levels.
Window state and size reports	CSI 11 t, 13 t to 16 t, 18 t, 19 t	Yes	State, position, text area and screen in pixels, cell size, text area in cells, and the largest it could be.
Push and pop the title	CSI 22 t, 23 t	Yes	Kept per terminal.
Title reports	CSI 20 t, 21 t	Opt-in	Answered only when window operations are allowed. A title is text the previous program chose, and the answer would land in the next program's input.
Window movement, resizing, minimizing and full screen	XTWINOPS, DECSLPP, DECSNLS, DECCOLM	Opt-in	Enable in Settings → Terminal → Privacy. Local and remote programs can then move or resize the window. Cell-size requests resize the window to fit the requested pane dimensions.

05.07/3 features

Character sets

Box-drawing characters and the older national character sets some programs still use.

Related development tests: 44 charsets cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
ASCII, UK, DEC special graphics, Technical and Supplemental, Latin-1	ESC ( ) * + - . / with B, A, 0, >, % 5	Yes	G0 to G3; locking and single shifts invoke them.
National replacement sets	DECNRCM (mode 42), SCS	Yes	The eleven VT200 national replacement sets, as listed in the VT510 manual. Designation requires DECNRCM.
Right-hand set (GR) and the VT500's Greek, Hebrew, Turkish and Cyrillic	LS1R LS2R LS3R	No	The GR designation is stored and reported by DECCIR but is not used to render UTF-8 input.

05.08/6 features

Color and text style

Text attributes, indexed and true color, and underline styles.

Related development tests: 65 sgr cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Bold, dim, italic, underline, inverse, hidden, strikethrough	SGR 1 2 3 4 7 8 9	Yes
16, 256 and true color	SGR 30–37 38 48 90–107, with ; or :	Yes
Underline styles	SGR 4:0 to 4:5, 21	Yes	None, single, double, curly, dotted, dashed.
Underline color	SGR 58, 59	Yes
Overline	SGR 53, 55	Yes	In the underline color when one is set.
Blink	SGR 5, 6	Partial	Text fades once a second; rapid and slow blink are identical. Text stays steady in background windows or with Reduce Motion enabled. Underlines and overlines do not blink.

05.09/10 features

Titles, folders, links and clipboard

Window titles, the current folder, clickable links, copy and paste, notifications.

Related development tests: 29 osc cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Window title	OSC 0, OSC 2	Yes	The terminal's name in its row, until it is renamed.
Current folder	OSC 7, OSC 9;9	Yes	A host other than this Mac, or a folder that isn't there, is ignored.
Hyperlinks	OSC 8	Yes	Web and mail links open with ⌘-click, a file: link on this Mac shows in the Finder, any other scheme is left alone.
Clipboard	OSC 52	Yes	Programs can write to the clipboard and query its contents.
Notifications	OSC 9, OSC 99, OSC 777	Yes	Under the app's notification settings. Chunked OSC 99 is joined.
Progress	OSC 9;4	Partial	Parsed and stored per terminal, but not displayed.
Prompt marks	OSC 133 A B C D	Yes	Command blocks, exit codes, busy or at the prompt.
Set, query and reset colors	OSC 4, 5, 10–19, 104, 105, 110–119	Yes	Overrides theme colors for the current terminal until reset. Queries return the active color. Named colors and CIE color formats are not supported.
Program status	OSC 7501	Yes	Wormhole's own protocol: idle, working, blocked, done or error becomes the terminal's status.
Pointer shape, systemd context, iTerm2 badges and marks	OSC 22, OSC 3008, OSC 1337 other than File=, OSC 21337	No	Ignored.

05.10/4 features

Graphics

Inline images using kitty, Sixel and iTerm2 protocols. Support differs by protocol.

Related development tests: 11 graphics cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
kitty graphics	APC G	Partial	Direct transfers (RGB, RGBA, PNG; zlib; chunked), placements with size and crop, deleting, queries, virtual placements with Unicode placeholders. Not supported: animation, file or shared-memory transfers, and relative placements.
Sixel	DCS q, modes 80, 8452	Partial	RGB and HLS colors, repeats, bands, raster attributes. Always starts with the VT340's colors: private palettes (mode 1070) are not read. ReGIS is not read.
iTerm2 inline images	OSC 1337 File=	Yes	PNG, JPEG, GIF's first frame; the multipart form. A file without inline=1 is a download, which the terminal does not do.
Limits on pictures		Yes	Pictures are untrusted input: at most 10,000 pixels on a side and 16 million per image, 32 MiB per command, 1,024 images in 128 MiB per terminal. A restored session brings back its text, not its pictures.

05.11/9 features

Unicode

Character widths and grapheme handling, using Unicode 18 data. Percentages below describe the recorded ucs-detect cases.

Related development tests: 52 unicode cases.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
Wide characters	East Asian Width	Yes	ucs-detect: 100.0% (506/506).
Narrow characters and combining marks		Yes	ucs-detect: 100.0% (5595/5595).
Invalid UTF-8		Yes	One U+FFFD per maximal subpart; a character split between two reads is joined.
Grapheme clusters	mode 2027	Yes	On from the start. CSI ? 2027 l turns it off for a program that counts code points; CSI ? 2027 $ p reports it.
ZWJ emoji		Yes	ucs-detect: 100.0% (1445/1445).
Emoji presentation (VS16)	U+FE0F	Yes	ucs-detect: 100.0% (426/426).
Text presentation (VS15)	U+FE0E	Yes	ucs-detect: 100.0% (158/158).
Flags (regional indicator pairs)		Yes	ucs-detect: 100.0% (262/262).
Scripts and languages		Yes	ucs-detect: 100.0% (6589/6589).

05.12/7 features

Keyboard and mouse

How your keys, mouse, scroll wheel and pastes reach the program.

Scroll horizontally to see all columns.

Feature	Sequence	Status	Notes
kitty keyboard protocol	CSI > u, < u, = u, ? u	Partial	Key encoding follows the flags requested by the program, with a separate stack per screen. Key-release, repeat and standalone modifier events are not sent.
DEC locator	DECELR DECSLE DECRQLP DECEFR	Yes	The mouse as a locator, for programs that ask for it. It replaces the xterm mouse reports while on.
Mouse click, drag and motion	modes 1000, 1002, 1003	Yes
UTF-8 and SGR mouse coordinates	modes 1005, 1006	Yes
Urxvt and pixel mouse coordinates, X10 mouse	modes 1015, 1016, 9	No	Recorded and reported by DECRQM, with no effect.
Focus reports	mode 1004	Yes
Alternate scroll	mode 1007	Yes	The wheel sends arrow keys on the alternate screen.

06/Terminal comparison

Terminal comparison

Documented support and results from the recorded test runs. See each cell’s source and limitations.

Unknown means we couldn't find it documented either way (we checked on October 15, 2026), not that it's missing. Terminal.app’s column uses only our measurements. iTerm2’s interrupted suite runs are marked Unknown. Documentation entries were checked on that date and may differ from current releases.

Scroll horizontally to see all columns.

Feature	Wormhole	Ghostty	kitty	WezTerm	iTerm2	Alacritty	Terminal
kitty graphics protocol	PartialNo animation, files or shared memory.	YesSource	YesSource	Unknown	YesSource	Unknown	Unknown
Sixel	PartialNo private palettes.	Unknown	Unknown	Partial"Preliminary and incomplete".Source	Unknown	Unknown	Unknown
iTerm2 inline images	Yes	Unknown	Unknown	YesSource	YesSource	Unknown	Unknown
Hyperlinks (OSC 8)	Yes	YesSource	YesSource	YesSource	YesSource	YesSource	Unknown
Clipboard (OSC 52)	Yes	YesSource	Unknown	PartialSet and clear; queries are ignored.Source	Unknown	YesSource	Unknown
kitty keyboard protocol	PartialNo key-release, repeat or standalone modifier events.	YesSource	YesSource	PartialA setting, off by default.Source	YesSource	YesSource	Unknown
Synchronized output (mode 2026)	Yes	YesListed as synchronized rendering.Source	Unknown	YesSource	Unknown	YesSource	Unknown
Grapheme clusters (mode 2027)Measured in this run	YesOn by default.	YesOn by default.	Noucs-detect finds no mode 2027.	UnknownNot measured: failed, no result within 1800s.	UnknownNot measured yet.	Noucs-detect finds no mode 2027.	Noucs-detect finds no mode 2027.
Desktop notifications	YesOSC 9, 99, 777.	YesOSC 9.Source	YesOSC 99, kitty's own.Source	YesOSC 9, 777.Source	YesOSC 9.Source	Unknown	Unknown
Prompt marks (OSC 133)	Yes	Unknown	Unknown	YesSource	YesSource	Unknown	Unknown
Progress (OSC 9;4)	PartialParsed but not displayed.	YesSource	Unknown	Unknown	Unknown	Unknown	Unknown
Underline styles and colors	Yes	Unknown	YesSource	YesSource	PartialCurly and color documented.Source	PartialUnderline color (SGR 58, 59) listed; the styles are not.Source	Unknown
ZWJ emoji widths (ucs-detect)Measured in this run	Yes100.0% (1445/1445)	Yes100.0% (1445/1445)	Yes100.0% (1445/1445)	UnknownNot measured: failed, no result within 1800s.	UnknownNot measured yet.	Partial0.7% (10/1445)	No0.0% (0/1445)
Emoji presentation (VS16)Measured in this run	Yes100.0% (426/426)	Yes100.0% (426/426)	Partial97.9% (417/426)	UnknownNot measured: failed, no result within 1800s.	UnknownNot measured yet.	Partial50.0% (213/426)	Partial50.0% (213/426)
Flags (regional indicators)Measured in this run	Yes100.0% (262/262)	Yes100.0% (262/262)	Yes100.0% (262/262)	UnknownNot measured: failed, no result within 1800s.	UnknownNot measured yet.	Yes100.0% (262/262)	Partial98.9% (259/262)
Screen checksums (DECRQCRA)Measured in this run	YesOff by default: an opt-in setting.	No	No	Yes	UnknownNot measured yet.	No	No
Text-area size (CSI 18 t)Measured in this run	Yes	Yes	Yes	Yes	UnknownNot measured yet.	Yes	Yes

Yes

Partial

Unknown